He found refuge in England on his father's death and, about 1095, William II of England recognised him as the rightful King of Scots. In return, Edgar agreed to hold Scotland as William's vassal. The following year, an English army helped Edgar to seize the throne from his uncle, Donald III. In 1100, his sister Matilda (Maud) married Henry I of England and so he became the English king's brother-in-law. Edgar's submissive attitude to England and his presentation of the Western Isles to the king of Norway led to his (insulting) nickname 'the Peaceable'.